Hot melt adhesive materials are currently applied by melting pellets or slats in a resistance heated reservoir, pumping the hot liquid with a resistance heated pump through a resistance heated hose, to heated valves and nozzles at the application point. Each of these individual zone temperatures are monitored and controlled. The startup of the system requires a delay for the material in the reservoir to melt. Flow resistance of viscous materials in the heated delivery hoses requires high fluid pressures.
Maintaining a reservoir of hot material, pressure pumping for distant delivery, and maintaining heat in the delivery system elements are all wasted electrical energy. Thermoplastic materials retained at application temperature for long periods and overheating in the system forms char [crystallized particles] that need to be filtered before clogging application nozzles. Localized over temperature spots are a result of resistance element heating not being able to adequately expose the majority of the material to a heat conduction element that is not in excess of the target temperature. Extended melted material exposure to the atmosphere in the melt reservoir requires material additives to counter oxidation.
Hot delivery elements, particularly delivery hoses, are a costly replacement item. Material changes are difficult and time consuming. The melt tank needs to be cleaned, and the pump delivery hoses purged. Higher melting temperature materials [400° to 450° F.] are particularly difficult to apply in the system. The invention addresses all of these problems in a small unit applied to localized melt and apply on demand.